Chapter 16Configuring Bridging
Introduction
The Smar tSwitc h 1800 supp orts tr an sparen t "spanni n g tree" bri d ging of non -routa ble
LAN traffic (e.g., NetBIOS, DECnet, AppleTalk) over frame relay between 802.3/
Ether ne t or 802. 5/Toke n Ring LAN s . The Smar tSwitc h also su pports t ransla t i onal
bridg i ng bet w een Eth er n e t a n d Token R i ng L AN s . (For m or e informa ti o n on bri dg i ng ,
refer to IEEE stan da rd 80 2.1 d. )
Bridgi ng supp ort incl u des:
●Encapsu lation of Ethe rn et and Tok en Ring t raffic per RFC 14 90 for tr a ns-
mission over frame relay
●Transparent Spanning Tree (802.1) bridging
●Translational bridging between Ethernet and Token Ring LANs
●Compatibility with Source Route Bridge environments
●"Self-learning" of MAC addresses for core bridging
●Forwarding of non-rou table LLC tra ffic such as NetBI OS, DECnet, Ap pleT alk,
LAT, and VINES
●Routin g/brid gi ng of IP an d IPX tra f fic
●MAC address filtering
●NetBIOS name filtering
●Bandwidth allocation
●Multivendor interoperability with other IEEE 802.1d devices
Routing transmits each packet based on its level-3 address, while bridging transmits
each frame based on its level-2 address. Athough some traffic can be either routed or
bridged, there is usually an advantage to doing one over the other. For instance,
bridging is generally easier to configure; however, routing can be more versatile.
IP and IPX traffic can also be bridged. (Brid ging can be enabled indiv iduall y for IP or
IPX; if enabled for either, all traffic of that type will be bridged.)
Neither IP (because of its ARP frames) nor IPX (because of its MAC
addressing structure) can be bridged successfully between Ethernet and
Token Ring LANs. (However, they can be routed between different LAN
types.)